/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.shardingsphere.data.pipeline.core.execute;
  
  import lombok.AccessLevel;
  import lombok.RequiredArgsConstructor;
  import lombok.SneakyThrows;
  import org.apache.shardingsphere.data.pipeline.core.exception.PipelineInternalException;
  import org.apache.shardingsphere.infra.executor.kernel.thread.ExecutorThreadFactoryBuilder;
  
  import java.util.Collection;
  import java.util.concurrent.BlockingQueue;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.function.BiConsumer;
  
  /**
   * Executor engine.
   */
  @RequiredArgsConstructor(access = AccessLevel.PRIVATE)
  public final class ExecuteEngine {
      
      private static final String THREAD_PREFIX = "pipeline-";
      
      private static final String THREAD_SUFFIX = "-%d";
      
      private static final ExecutorService CALLBACK_EXECUTOR = Executors.newSingleThreadScheduledExecutor(ExecutorThreadFactoryBuilder.build(THREAD_PREFIX + "callback" + THREAD_SUFFIX));
      
      private final ExecutorService executorService;
      
      /**
       * Create task execute engine instance with cached thread pool.
       *
       * @param threadName thread name
       * @return task execute engine instance
       */
      public static ExecuteEngine newCachedThreadInstance(final String threadName) {
          String threadNameFormat = THREAD_PREFIX + threadName + THREAD_SUFFIX;
          return new ExecuteEngine(Executors.newCachedThreadPool(ExecutorThreadFactoryBuilder.build(threadNameFormat)));
      }
      
      /**
       * Create task execute engine instance with fixed thread pool.
       *
       * @param threadNumber thread number
       * @param threadName thread name
       * @return task execute engine instance
       */
      public static ExecuteEngine newFixedThreadInstance(final int threadNumber, final String threadName) {
          String threadNameFormat = THREAD_PREFIX + threadName + THREAD_SUFFIX;
          return new ExecuteEngine(Executors.newFixedThreadPool(threadNumber, ExecutorThreadFactoryBuilder.build(threadNameFormat)));
      }
      
      /**
       * Submit a {@code LifecycleExecutor} with callback {@code ExecuteCallback} to execute.
       *
       * @param pipelineLifecycleRunnable lifecycle executor
       * @param executeCallback execute callback
       * @return execute future
       */
      public CompletableFuture<?> submit(final PipelineLifecycleRunnable pipelineLifecycleRunnable, final ExecuteCallback executeCallback) {
          return CompletableFuture.runAsync(pipelineLifecycleRunnable, executorService).whenCompleteAsync((unused, throwable) -> {
              if (null == throwable) {
                  executeCallback.onSuccess();
              } else {
                  Throwable cause = throwable.getCause();
                  executeCallback.onFailure(null != cause ? cause : throwable);
              }
          }, CALLBACK_EXECUTOR);
      }
      
      /**
       * Submit a {@code LifecycleExecutor} to execute.
       *
       * @param pipelineLifecycleRunnable lifecycle executor
       * @return execute future
       */
      public CompletableFuture<?> submit(final PipelineLifecycleRunnable pipelineLifecycleRunnable) {
          return CompletableFuture.runAsync(pipelineLifecycleRunnable, executorService);
      }
      
     /**
      * Shutdown.
      */
     public void shutdown() {
         if (executorService.isShutdown()) {
             return;
         }
         executorService.shutdown();
         executorService.shutdownNow();
     }
     
     /**
      * Trigger.
      *
      * @param futures futures
      * @param executeCallback execute callback on all the futures
      * @throws PipelineInternalException if there's underlying execution exception
      */
     @SneakyThrows(InterruptedException.class)
     public static void trigger(final Collection<CompletableFuture<?>> futures, final ExecuteCallback executeCallback) {
         BlockingQueue<CompletableFuture<?>> futureQueue = new LinkedBlockingQueue<>();
         for (CompletableFuture<?> each : futures) {
             each.whenCompleteAsync(new BiConsumer<Object, Throwable>() {
                 
                 @SneakyThrows(InterruptedException.class)
                 @Override
                 public void accept(final Object unused, final Throwable throwable) {
                     futureQueue.put(each);
                 }
             }, CALLBACK_EXECUTOR);
         }
         for (int i = 1, count = futures.size(); i <= count; i++) {
             CompletableFuture<?> future = futureQueue.take();
             try {
                 future.get();
             } catch (final ExecutionException ex) {
                 Throwable cause = ex.getCause();
                 executeCallback.onFailure(null != cause ? cause : ex);
                 throw new PipelineInternalException(ex);
             }
         }
         executeCallback.onSuccess();
     }
 }